It is known that an image forming apparatus has a heating member that is heated by a powered heat source, a temperature sensor for detecting the temperature of the heating member, and a control device for controlling the heat source based on the temperature detected by the temperature sensor.
This control device is configured to control a timing to supply electric power to the heat source (to turn on the heat source), according to the heated state of the vicinity of the heating member.
In other words, the control device is configured such that when the control device receives a print instruction, if the temperature detected by the temperature sensor is low, the control device supplies electric power to the heat source at an early timing; whereas if the temperature detected by the temperature sensor is high, the control device delays the timing to supply electric power to the heat source.